I'd never dream of it. But chow.com's etiquette expert says it's the thing to do. http://www.chow.com/stories/10496
You order an entree, it comes perfectly prepared and just as advertised. But you decide you just aren't in the mood for it. (Or maybe, though correctly described on the menu, it is not quite what you expected.) So you send it back and don't pay for it. As I said, I wouldn't dream of it. (Even if they bring the wrong order, I don't say a word so as not to get the waiter in trouble.) But I'm curious. Would anyone here consider doing it?